1. Field of the Invention
The present invention concerns a mechanism for detachably fitting a male fixing member and a female engaging member and, particularly, it relates to an engaging mechanism suitable for the engagement of metal fittings of binders, etc.
2. Description of the Prior Art
As engaging mechanisms for detachably fitting a head of a rod-like male fixing member and a female engaging member, for example, in metal fittings of a paper binder, there has generally been known such a mechanism comprising a combination of a male fixing member having a head of a larger diameter and a neck of a smaller diameter contiguous therewith which are formed near the top end of the member and a plate-shaped female engaging member having a hole in which an aperture of larger diameter for receiving the head of the fixing member and a narrow elongate aperture contiguous therewith for engaging the neck of the fixing member. Metal fittings of the paperbinder having such a mechanism are disclosed, for example, in Japanese Utility Model Publication No. Sho 28-5809, Japanese Utility Model Laid-Open Publication No. Sho 53-91731 and Japanese Utility Model Publication No. Sho 55-56067.
In the engaging mechanism of this type, the head of the fixing member is at first inserted from the larger diameter portion of the hole in the engaging member, and then the neck of the fixing member is engaged to the narrow elongate aperture of the hole in the engaging member by relatively displacing the position between the fixing member and the engaging member, thereby fitting both of the members to each other not separably. The fitting between both of the members can be released by the operations in reverse of the above.
In this structure, however, if an external force is accidentally exerted on the fixing member or the engaging member, both of the members often detach undesirably, thereby bringing about a problem in the reliability.